Prevent Emacs from exiting once the exit procedure has initiated?

Question

Is there a way to prevent Emacs from exiting once I initiate the exit process?

I occasionally fat finger C-xC-s as C-xC-c. It isn't an awful process to get back up and running but I am curious if there is a way I can stop the exit process so that I can continue uninterrupted with all my files open.

Using GNU Emacs 24.3.1. Running on Cygwin under Window 7.

Gramophone

Even though I accepted scottfrazer's answer, I am thankful for the alternate methods shown. – Gramophone

I couldn't find this question, so I posted the same question: a confirmation after C-x C-c before exiting Emacs. – Dialectic

Answer 1

There is a built-in variable you can set to a function like so:

(setq confirm-kill-emacs 'y-or-n-p)

Retorsion

By default, Emacs uses 'yes-or-no-p when you try to exit Emacs and there are unsaved buffers. For consistency, if you'd like the prompt when closing Emacs to be the same as this default, use (setq confirm-kill-emacs 'yes-or-n-p) instead. – Plessor

You can set this with customize – Jehoshaphat

@Plessor wouldn't (setq confirm-kill-emacs 'yes-or-no-p) be more consistent, rather than (setq confirm-kill-emacs 'yes-or-n-p)? – Impassible

Answer 2

scottfrazer's answer's the more appropriate, to me, than what follows.

Enable Emacs Lock minor mode (emacs-lock-mode) on any of the buffers, to prevent Emacs from exiting in case you accidentally hit C-xC-c.

From the Emacs Wiki page:

Emacs cannot exit until the buffer is killed or unlocked

Add (emacs-lock-mode) to your .emacs/init.el file so that this lock is enabled in every Emacs session. Adding this will lock the *scratch* buffer which will have to be unlocked in case you really want to exit Emacs.

Another way/hack of doing this is to start a process in Emacs e.g. M-xshell or have an unsaved file associated to a buffer, doing this will prompt you for confirmations when Emacs is exiting.

Yes one more, unset C-xC-c using global-unset-key. And then if you want to exit Emacs M-xkill-emacs.

Decagon

Answer 3

• Using confirm-kill-emacs, as @scottfrazer suggested, is one approach.

• More generally, you can use kill-emacs-query-functions to do whatever you want in this regard. (There was no real need for them to add confirm-kill-emacs, but they did.)

• You probably do not want to use kill-emacs-hook in this regard (that's what kill-emacs-query-functions is for), but be aware of it, in case you come across it using apropos etc.

One advantage of kill-emacs-query-functions over justconfirm-kill-emacs is that you can require a better confirmation: yes instead of just hitting key y. For example:

(add-hook 'kill-emacs-query-functions
          (lambda () (y-or-n-p "Do you really want to exit Emacs? "))
          'append)

That is what I do. It is too easy to be hitting keys and accidentally hit C-x C-c y, especially since I have similar keys bound (e.g., C-x c, C-x C-x, C-x C-y).

Elson

Answer 4

I've added the following to my emacs configuration to prevent accidental closes. I didn't like having to confirm close emacs for something like a one off commit, but I hate losing my emacs session accidentally while deep in a problem.

This adds a global state flag to emacs describing whether or not it's locked. This flag is set either automatically after emacs is open for 5 minutes, or manually using the lock-emacs command. The lock can later be removed manually by using the unlock-emacs command.

If emacs is locked, and you attempt to close it (presumably accidentally), emacs will instead give you a message saying that emacs has been locked, and cannot be closed. If it's unlocked, close behaves exactly as it does by default.

;; don't close emacs on accident
(setq emacs-locked nil)
(setq confirm-kill-emacs
      (lambda (&rest args)
        (if emacs-locked
            (progn
              (message "%s" "Emacs is locked, and cannot be closed.")
              nil)
            t)
         ))
(defun lock-emacs-silently ()
  (progn
    (setq emacs-locked t))
  )

(defun lock-emacs ()
  "Prevent emacs from being closed."
  (interactive)
  (progn
    (lock-emacs-silently)
    (message "%s" "Emacs is now locked."))
  )
(defun unlock-emacs ()
  "Allow emacs to be closed."
  (interactive)
  (progn
    (setq emacs-locked 'nil)
    (message "%s" "Emacs can now be closed."))
  )
(run-at-time "5 minutes" nil 'lock-emacs-silently)

(Open to suggestions on how to make the confirm-kill-emacs portion nicer, I'm a lisp novice :) ).

---

After using this for a couple of years, I ended up going to something much simpler:

;; Unbind the normal close
(global-unset-key (kbd "C-x C-c"))
;; Require C-c 3 times before closing
(global-set-key (kbd "C-x C-c C-c C-c") 'save-buffers-kill-terminal)

Mae

Answer 5

If you're looking for a shorter answer, I've had this line at the bottom of all my .emacs files since the last century:

(shell)

Watereddown

Can you explain what adding (shell) does? I'm searching through the emacs wiki and just searching "shell" is a bit ambiguous to find out what this does. – Gramophone

I have mentioned it in my answer. (shell) actually starts a process which Emacs will prompt you for being active and if you really want to exit. Shell Mode. – Decagon